[Ada] Performance degradation with references

This patch modifies the creation of markers for variable references in the context of SPARK elaboration checks. Previously, prior to checking whether a reference requires such a marker, the compiler performed a logarithmic look up to determine whether the reference appears within a call. This action caused the compiler to degrade when a source program contains multiple (100,000s) references. Now, the compiler no longer performs the look up immediately.

2018-06-11 Hristian Kirtchev

gcc/ada/

- sem_ch8.adb (Find_Direct_Name): Mode the declaration of Is_Assignment_LHS further in. Use predicate Needs_Variable_Reference_Marker to determine whether to create avariable marker. (Find_Expanded_Name): Mode the declaration of Is_Assignment_LHS further in. Use predicate Needs_Variable_Reference_Marker to determine whether to create a variable marker.- sem_elab.adb (Build_Variable_Reference_Marker): Remove the various checks that determine whether the identifier or expanded name is a suitable variable reference. The checks are now performed by Needs_Variable_Reference_Marker.- sem_res.adb (Resolve_Actuals): Use predicate Needs_Variable_Reference_Marker to determine whether to create avariable marker.- sem_util.adb (Needs_Variable_Reference_Marker): New routine.- sem_util.ads (Needs_Variable_Reference_Marker): New routine.